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Showing 1 to 20 of 44 for “"olefin metathesis"”.
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A mechanistic study of the olefin metathesis reaction
Thesis (M.S.)--Michigan State University. Dept. of Chemistry, 1972
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Mechanisms and catalyst design for heterogeneous Olefin metathesis
Olefin metathesis offers a promising technology for on-purpose production of propylene and has been implemented in several industrial processes including the Lummus Olefin Conversion Technology. However, current metathesis technology cannot produce propylene cheaply and efficiently due to reliance …
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The evolution of molybdenum and tungsten olefin metathesis catalysts
… diffraction. The initial reactivity with simple olefins employing many of these new alkylidenes was explored. Chapter 2: Two diastereomers of the MAP (monoaryloxidepyrrolide) species, W(NAr)(CH2)(Me2Pyr)(OBitetBr2) (OBitetBr2 = (R)-3,3'-dibromo-2'-(tertbutyldimethylsilyloxy)- …
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Molybdenum alkylidene complexes : syntheses and applications to olefin metathesis reactions
… Characterization and Activity as Chiral Olefin Metathesis Catalysts. Molybdenum olefin metathesis catalysts that contain previously unexplored aliphatic 1- phenylcyclohexylimido (PhCyN) and 2-phenyl-2-adamantylimido (PhAdN) groups were prepared and shown to be efficient and selective in a …
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Development and exploration of Schiff base ruthenium carbene catalysts for olefin metathesis
… overview is presented on the history of metathesis catalysts, the current ideas in organometallic thinking and the theoretical accounts on Ru-metathesis catalysts. The second part deals with the synthesis and activity of Schiff base substituted second generation Grubbs catalysts, …
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High-oxidation-state molybdenum and tungsten monoalkoxide pyrrolide alkylidenes as catalysts for olefin metathesis
Chapter 1 describes work toward solid-supported W olefin metathesis catalysts. Attempts to tether derivatives of the known Z-selective catalyst W(NAr)(C₃H₆)(pyr)(OHIPT) (Ar = 2,6- diisopropylphenyl, pyr = pyrrolide; HIPT = 2,6-bis-(2,4,6-triisopropylphenyl)phenyl) to a modified silica surface by …
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Ruthenium K-edge X-ray absorption spectroscopy studies of ruthenium complexes relevant to olefin metathesis
… study of the widely-employed ruthenium-catalysed olefin metathesis reaction, the finer mechanistic details have not been elucidated. An area that is noticeably lacking is spectroscopic exploration of the relevant complexes. In this work, organometallic ruthenium complexes of importance to olefin …
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Z-selective olefin metathesis processes and Cis/syndioselective ROMP with high oxidation state molybdenum alkylidenes
… silicasupported tungsten alkylidynes. The alkyne metathesis activity of all new homogeneous and heterogeneous alkylidyne complexes is reported. Chapter 2: Addition of one equivalent of 2,4,6,2',4',6'-hexaisopropylterphenol to Mo(NAd)(CHCMe 2Ph)(pyr)2 results in the formation of Mo(NAd)(CHCMe …
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Investigations of sterically demanding ligands in molybdenum and tungsten monopyrrolide monoalkoxide catalysts for olefin metathesis
… understanding of the role of steric hindrance in olefin metathesis catalysts. A new synthetic route to imido alkylidene complexes of Mo and W, which proceeds through mixed-imido compounds containing both NAr* and NtBu ligands, was developed to incorporate the NAr* ligand. Alkylidene formation is …
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Molybdenum and tungsen alkylidene species for catalytic Enantio-, Z-, and E-selective olefin metathesis reactions
CHAPTER1 A general introduction to olefin metathesis is given. Highlights include a detailed discussion of group VI imido alkylidene catalysts. CHAPTER 2 Several bispyrrolide species Mo(NAr)(CHCMe 2Ph)(pyr)2 (Ar = 2,6-i-Pr2C6H3, pyr = 2,3,4,5- tetramethylpyrrolide, 2,5-diisopropylpyrrolide, or …
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Synthesis of molybdenum(VI) alkylidene complexes as catalysts for living polymerizations of terminal acetylenes and olefin metathesis
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1993.
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Synthesis and reactivity of high oxidation state tungsten and molybdenum olefin metathesis catalysts bearing new imido ligands
… of the type W(NAr)(CHCMe3)(OR)2. Ring-Opening Metathesis Polymerization (ROMP) studies using a series of these bisaryloxides show that rates of ROMP increase as the electron-withdrawing power of the substituents on the imido ligand increase if steric bulk about the metal center is held …
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High oxidation state molybdenum and tungsten imido alkylidene and metallacycle chemistry : catalytic asymmetric olefin metathesis and mechanistic investigation
… for representative asymmetric ring- closing metathesis reactions. Both catalysts were compatible with a variety of common functional groups. Intermediate tungstacyclobutane complexes were observed when a stoichiometric amount of desymmetrization substrate 62 was added to 23a. The final stable …
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I. Kinetic and mechanistic studies of dynamic alkyne metathesis and II. Towards regenerative thermosets using frontal ring-opening olefin metathesis polymerization
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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Functionalization of metal-organic frameworks with early transition metals : from fundamental studies to catalytic applications
… is used to synthesize novel catalysts for the olefin metathesis reaction. In Chapter 1, the reader is introduced to post-synthetic modification of MOFs with a focus on early transition metal species. A review of pertinent literature is presented. Chapter 2 describes how a desire to challenge …
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Self-Condensing Ring-Opening Metathesis Polymerization
Ring-opening metathesis polymerization (ROMP) is a great tool for synthesizing polyolefin materials with different topologies, including hyperbranched polymers—polymers with high degrees of branching and many end groups. However, hyperbranched polymer synthesis via ROMP is challenging due to …
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Thermal decomposition studies on metallacycloalkanes and their precursors
… transition metals. These transformations include olefin metathesis, ethylene oligomerization etc. The studying of thermal decomposition behavior of these compounds can help us to understand the termination step in the mechanism of these transformations. This thesis describes the thermal …
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Synthetic investigations of molybdenum pyrrolide and related complexes
CHAPTER 1: A general introduction to olefin metathesis is given. Highlights include a historical perspective of the development of olefin metathesis and a detailed discussion of group VI imido alkylidene catalysts. CHAPTER 2: Monosiloxide and disiloxide complexes have been prepared through the …
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Synthesis and dynamics of [gamma]-alumina supported molybdenum subcarbonyls and model compounds
… on 𝛾-alumina is a precursor to an active olefin metathesis catalyst. Surface sites on the alumina act as coordinating ligands to stabilize various molybdenum subcarbonyl species. The formation of these species can be controlled by appropriate activation conditions. In particular, …
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